Vacuum tube circuit



Feb. 19, 1935. E; E. TURNER, JR 1,991,430

VACUUM TUBE CIRCUIT Filed Sept. 20, 1927 20 STANDARD ATTORNE s PATENT OFFICE Y ACUUM TUBE cmourr Edwin E. Turner, Jr.,' West Roxbury. Mass, as-

signor to Submarine Signal Company, Boston, Mass., a co p ration of Maine Application September 20, 1927, Serial No. 220,719 7 Claims. (01. 177-352).

UNITED STATE The present invention relates to the means and .method of controlling the restoration of a relay circuit of the general type herein shown as well as the types of circuits shown in my copending United States patent application which matured into Patent No. 1,775,073. In my application just referred to, the circuit of the last tube is restored to normal, pre-operating condition by the fact that the grid return is connected to the positive side of the filament and that after the phenomenon has passed the grid assumes the positive potential of, the positive side of the filament. Since this is substantially instantaneous, the cir cult is brought back to normal condition immediately after operation. In the modification of Figure 3, the circuit is restored to normal condition by operation of the switch 25, which brings the potential of the grid to that of the filament.

The present invention is chiefly concerned with the regulation of the restoration of the cir-' cult to normal conditions automatically but not instantaneously.

Not onlyis it possible to adjust the interval between operation and restoration to any desired value, but it is also possible,.by the methods of the present invention, to vary this interval by proper controlling devices. If, for instance, it is desired to insure that the circuit remain inoperative for one second, certain electrical constants may be so adjusted, as will be explained later, as to accomplish this result. A device of this nature is particularly useful in recording sound phenomena which are followed by other phenomena which are not desired and which; therefore, are eliminated by making the circuit remain inoperative during the necessary interval to exclude the undesired phenomena. Another useful purpose to which the present invention may be put is the measurement of a time interval. If the values of the constants of the restoration circuit are known relative to the time intervals, then the interval between two operations of the circuit occurring directly at the'beginning and at the restoration of the circuit can be measured by the constants of the circuit.

operating the relay- 12 of the output circuit 13. In place of the relay in the output circuit, the impulse or the signal in the transformer winding 11 may be made to operate any kind of indicating circuit which may be desired, as, for instance, a discharge tube such as indicated in my copending application mentioned above. The impulse from the receiver 1 may be put through a filter or an amplifier 2 and thereafter impressed upon the time control circuit by means of the transformer 3, the secondary of which is connected to the grid of the vacuum tube 7. v The grid of the vacuum tube 7 is normally maintained at a negative potential by means of the battery 4 and the resistance 5 across the filament leads, which arrangement allows an adjustment of the potential upon the grid of the tube 7 within the range of the voltage used for the filaments. The plate of the tube 7 is maintained at a potential positive with respect to the filament by means of the battery 6, which has its positive side connected to the plate and its negative side connected through the resistance 9 to the filament of the tube '7. In shunt with the resistance 9 is a condenser 10, the operation of which will be explained a little later. The plate circuit of the tube '7 is coupled to the tube 8 by means of the grid lead 18 connecting from the upper end. of the resistance 9 to the grid of thetube 8. A filament battery of necessary power is indicated between the taps 14 and 15 and is used to supply the filaments with heating current while the plate voltage of the second tube is supplied by the power source between the terminals 16 and 17.

The operation of the circuit is as follows: When an impulse is first received by the receiver 1, it

circuit is positive, the plate filament current in the tube 7 will increase and thereby, since the current in the outer circuit is thought of as flowing from filament to plate, the point A will increase in potential with respect to the point B. As for point'B, it will be negative with respect to the point A and the tendency in tube 8 will be for the grid to prevent the flow of electrons from the filament to the plate of that tube.

As shown in my copending application mentioned before, this efiect may be made so rapid that the current will be sharply broken in the plate circuit of the tube 8. This sharp interruption of the plate filament current of the tube, is

readily useable for the operation of any desired signal or indicator. As has been stated in the copending application, however, when-such circuit has been used'it has not restored itself automatically to normal conditions; but .in the present invention, by the use of the condenser 10 and an extremely high resistance 9, it is possible to control the restoration of the circuit by suitably selecting the time constant due to the presence of resistance and capacity in the .circuit. The opermal, preoperating condition with respect to the.

point A. The rate of discharge of the condenser 10 through the resistance 9 controls the period of restoration of the circuit.

By selecting proper Values of resistance and capacity in the present circuit, it has been possible to delay the normal restoration of the circuit from a very small fraction of a second to a number of seconds. It is thus possible to allow one operation of the circuit and prevent any further operation until it is restored to normal conditions by means of the condenser and resistance, which may be adjusted for practically any desired time interval.

In Figure 2 is shown an application of the circuit for the method of measuring the accuracy of a timing mechanism, such as a watch or clock, against a given standard. A standard clock or chronometer is indicated at 20 and the watch to be tested at 21. Individual microphones 22 and 23, associated respectively with the standard and the watch to be tested, are connectedin circuit with the transformers 24 and 25 forming the input tothe time control circuit of the same type as indicated in Figure 1, with the exception that the condenser 10 and the resistance 9 are variable.

I and adjustable. Also, in addition to" the relay coil 11 and the relay 12, an,indicator 26 is shown, as well as switches 27 and 28, the former for operating the circuit in connection with the coil 11 and the relay 12 and the latter for operating a neon or discharge tube 29 through the transformer 30.

The method of operation of the circuit in Figure ,2 is as follows: The microphone 22 is placed over the standard time piece and the ticks are transmitted from the time piece through thecircuit either to the neon tube or the indicator, either causing a flash of the former or some sort of an indication in the indicator. The ticks of the standard will therefore be repeated in the same uniform interval. The watch to be compared, 21 in Figure 2, will then be placed beneath the microphone 23. Presumably the ticks of the standard and the watch will be out of phase and follow one another with some definite interval between, which interval will gradually change if the watch to be adjusted is not going properly. The condenser 10 and the resistance 9 are therefore adjusted to the point which will just allow the ticks of both the standard and the watch 21 to come through to the indicator. If, now, after a short time, only one tick comes through, it is evident that the time interval between the ticks of the standard and the watch 21 has decreased.

knowing the calibration of the condenser and resistance for the equivalent time interval, the loss or gain of the watch over the period is easily determined. It the interval increases so that both ticks continue to appear, a second adjustment can still be made to the point where both ticks will just appear. This increased time interval will also give a measure of the change of the watch with respect to the standard. If, 01 course, the interval continuesto remain the same, the watch 21 and the standard are going alike.

It will be readily understood that if the time interval from the ticking of the standard to that of the watch is increasing, the complementary time interval from the tick of the watch 'to that of the standardis decreasing, and that if it is de-' sired in the measurement and adjustment to have one tick disappear, the observation can always be made on the decreasing time interval.

In this manner, instead of waiting a long time, days for instance, to determine the rate of change of a watch with a standard, it may be made much quicker with accuracy.

Another important use of the present invention isin connection with the determination of distance by sound and electromagnetic waves. .In Figure 3 is shown such an arrangement. Simultaneous signals are sent out by the radio antenna 40 and the submarine oscillator 31 by means of the cams 32 and 33 respectively operating in synchronism to connect the generator 34 therewith. The signals are received on the receiving antenna 35 and the hydrophone v36, the radio signal on former 37, to the time control circuit, and the submarine signal through the transformer 38 to the same circuit. An adjustable impedance 39, in place of the condenser and resistance of Figures 1 and 2, is provided for measuring the time interval between the receipt of the radio and the submarine signals. This impedance may be calibrated in units of distance, as shown in Figure 3. The, measurement may be made either by adjusting the impedance 39 until the submarine signal disappears or by adjusting the impedance until it just appears. A good method to follow is to make the measurement in both ways and then take a mean value for the distance.

Having described my invention, I now claim:

1. A vacuum tube relay circuit comprising a detector tube'and circuit having a grid filamentcircuit including means normally keeping the grid at a negative potential with respect to the filament, means operable to overcome the negative bias of the grid, a second tube and circuit including an indicator in the output thereof, and conductive means coupling the filament plate circuit of said first tube with the filament grid circuit of said second tube, said coupling means comprising means for automatically producing on operation a rapid potential change on the grid of the second tube and a slow return of the grid to itsgpreoperative condition.

2. A signal relay circuit for receiving a signal and preventing the reoperation of an indicator ducing an increase in plate filament current of said valve by the receipt of the signal, a second thermionic valve circuit having a grid directly coupled througli an electromotive force source to the plate of said first valve, the positive side of theelectromotive force being connected to the plate, and a condenser and resistance having respectively low capacity and high resistance connected in parallel across the grid filament ofthe second valve and plate filament of said first valve,

said condenserand resistance adapted to allow the grid of the second valve to assume substantially instantaneously the potential ofthe plate for a definite time interval after its initial operation comprising a thermionic valve and circuit including means for producing an increase in plate filament current of said valve by the receipt of the signal, a second thermionic valve circuit having a grid coupled directly and conductively through an electromotive force source to the plate of said first valve'and means connected across the grid filament of the second valve and plate filament of said first valve adapted to allow the grid of the second valve to assume substantially instantaneously the potential of the plate of the first valve and substantially hold this potential for a definite time after the operation of the circuit by the signal.

4. A signal relay circuit for receiving a signal and preventingthe reoperation of an indicator for a definite time interval after its initial operation comprising a thermionic valve and circuit including means for producing an increase in plate filament current of said valve by the receipt of the signal, a second thermionic valve circuit"; t

having a grid coupled directly and conductively through a battery to the plate of said first valve and means connected across the grid filament of the second valve and plate filament of said first valve adapted to allow the grid of the second valve to assume substantially instantaneously the potential of the plate of the first valve and substantially hold this potential for a definite time after the operation of the circuit by the signal.

5. A vacuum tube relay circuit comprising a detector tube having a plate filament and a grid,

and means for normally biasing said grid negatively with respect to the filament, a second tube includinga grid circuit and a circuit including an indicator in the outputthereoi and means directly and conductively coupling the plate circuit of said first tube with the grid circuit of second tube, said coupling means comprising means for automatically producing on operation a rapid potential change on the grid of the sec-' i cud tube and a slow return of the grid to its preoperative condition.

EDWIN E. TURNER, JR. 

